Manufacture of containers and tubes from sheet metal



Mam}! 1931 J. H. E. FRANCIS ET AL ,796,0

MANUFACTURE OF CONTAINERS AND TUB ES FROM SHEET METAL Filed April 16,1928 IN VENTORS.

Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE JAMES HENRY EDWARDFRANCIS, OF DEPTFORD, LONDON, AND RICHARD CONGDON COATH, OF LEWISHAM,LONDON, ENGLAND MANUFACTURE OF CONTAINERS AND TUBES FROM SHEET METALApplication filed April 18, 1928, Serial No. 270,378, and in GreatBritain May 5, 1927.

This invention relates to improvements in the manufacture of kegs,drums, tin boxes, and other containers and tubes from sheet metal, andrelates more articularly to the formation of the longitudinal joint ofsuch articles made from sheet metal. Such a joint is usually made by asimple interlocking of the longitudinal edges of the metal, and theresultin joint is usually neither air or water tig t, nor sufiicientlyrobust to stand deformation without opening, and the object of thepresent invention is to overcome these drawbacks in a simple andreliable manner.

The present invention comprises a liquid tight joint in which the edgesof the metal are so interlocked that five thicknesses of metal arefolded together either on the inner side to produce a perfectly smoothexterior surface or on the outer side to produce a smooth interiorsurface.

This invention will now he more particularly described making referenceto the accompanying drawing in which:

Fig. 1 is an enlarged end view of two edges of sheet metal showing thepreliminary jointing method for producing a joint according to oneembodiment of the present invention.

-Fig. 2 is a similar view of a further step in the method,

Fig. 3 is a similar view of the completed joint.

Throughout the views similar parts are marked with like letters ofreference.

In the embodiment of the present invention, shown in the drawings, thetwo longitudinal ed es a and b of the sheet metal are first so s aped,preferably by stamping that the one edge a is formed of a channel orU-shape in cross section fitting within the other edge 6 correspondinglyshaped, see Fig. 1.

The channel so formed is preferably below the exterior surface orprojects inwardly. The right angled bends a and b of the metal areslightly radiused or rounded and those at the first or outer bends a 6are so curved as to project slightly above the exterior surface, asshown.

The preliminary joint so formed is then slightly flattened, see Fig. 2,so as to cause the channel shaped groove to assume a dovetail shape incross section, with the base or larger side of the dovetail on the innerside, said base retaining the width of the original channel shape sothat the first or outer bends a b thereof will be closer together.

In the next operation, see Fig. 3, the dovetail is squeezed flat so asto produce the finished oint in which each original edge is so foldedand interlocked as to produce a five fold thickness of metal at thejoint. The interlocked joint so produced has a smooth and even exteriorsurface.

The flattening or closing operations above described are also preferablyperformed by stamping, but all operations may be performed by rolling orin other convenient manner.

In the above described construction, the folds of metal constituting thejoint project inwardly so as to produce a smooth exterior surface, butit will be readily seen that the folds may be so arranged as to projectoutwardly to produce a smooth interior surface.

Although the joint is shown and described as being made in threeseparate operations,

it will be understood that more or less than three separate operationsmay be employed to attain the desired end.

It will be appreciated that a joint so formed, is not onl immenselystrong, but is also air and hquid; ti ht without the necessity ofwelding or sol ering.

We declare that what we claim and desire to secure by Letters Patentis 1. The method for making a joint for containers and tubes made fromsheet metal, firstly by forming both edges of the metal of a U-shape incross section fitting one within the other, the first or outer bendsbeing curved to project slightly above the exterior surface, secondlyflattening the U-shaped groove so formed to cause it to assume adovetail shape in cross section and thirdly squeezing the dovetail flatto produce a ffinislllied five fold interlocking joint, as set ort 1 2.The method for making a joint for containers and tubes made from sheetmetal in which a five fold djoint is roduced firstly b stamping both eges of t e metal into a U shape in cross section one within the otherand having the first or outer bends curved to project slightly above theexterior surface (see Fig. 1), secondly sli htly flattening thepreliminary joint so ormed as to cause the U-shaped groove to assume adovetail shape in cross section withthe base or larger slde of thedovetail on the inner side (see Fig. 2) and finally squeezing thedovetail flat to produce a five fold interlocking joint, as shown inFig. 3, as set forth.

JAMES HENRY IEDWARDI FRANCIS. RICHARD CQNGDON COATH.

